Managed to do the separated HBWC trick, but in a .32SWl rather than a .38. Can warm them up to the point where it blows the nose off. In my case, it made two holes on paper for one pull of the trigger, and I notieced that it did and ceased fire. Could have left the "lead tube) stuck in the bore, but didn't.
I'd let the gun decide what it likes best rather than loading up a pile of ammo on someone's recommendation. Might like 2.5gr. Might like 2.7. Might like 2.9. <ight not like Bullseye at all and prefer a different powder.
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Once was more serious about target shooting. Had a very nice Clark custom .38 wadcutter gun built on a Colt 1911 (ues, flush seated .38WC loads only). Lots of experimentation, but that gun turned out to NEED 2.9gr. of BE/ Speer 148gr. HBWC to shot to it's best.
Got a S&W 52 (another .38 special WC semi-auto). Would not shoot that load for sour snail snot AND showed evidence of being over-driven by that charge. Shame as i had about 1100 of that load ready for practice. TheS&W would move along just fine with 2.5gr. of Red Dot.
Point being this: each gun is a picky eater. The above semi-autos would show more of a variation that any revolver I'd tried, but revolvers have the same picky-eater habit.